The present invention relates to a hologram recording film with additional information and also pertains to a recording method therefor. More particularly, the present invention relates to a hologram recording film having a reflection type volume hologram of a three-dimensional object or the like recorded therein, together with a plane pattern, e.g. a character or an image, recorded in superimposition with the volume hologram as individual information (variable information) concerning the associated hologram. The present invention also relates to a recording method for the hologram recording film.
To record a reflection type volume hologram, a volume hologram photosensitive material, e.g. a photopolymer, is placed in close contact with or in close proximity to a reflection type volume hologram original plate for duplication, and illuminating light for duplication is applied from the hologram photosensitive material side so that reflected and diffracted light from the reflection type volume hologram original plate and the incident light interfere with each other in the hologram photosensitive material, thereby duplicatively recording a reflection type volume hologram having the same characteristics as those of the reflection type volume hologram original plate. To add variable information, e.g. a serial number, to each individual hologram made by holographic duplication, some methods have heretofore been proposed. For example, Japanese Patent Application No. Hei 10-56470 discloses a method wherein a reflection mask using a reflection type liquid crystal display is provided in the vicinity of a hologram on a hologram original plate that is to be duplicated, and additional information corresponding to a reflection pattern of the reflection mask is recorded on a hologram photosensitive material at the same time as the hologram to be duplicated is recorded. In addition, Japanese Patent Application No. Hei 10-56470 discloses a method wherein a reflection region is provided on a hologram original plate in the vicinity of a hologram to be duplicated, and light is applied to the reflection region through a transmission mask using a transmission type liquid crystal display to record additional information corresponding to a transmission pattern of the transmission mask on a hologram photosensitive material simultaneously with the hologram.
Japanese Patent Application No. 2000-4617 proposes a recording method wherein when a hologram is to be recorded by duplication from a reflection type hologram original plate, a character hologram plate for reproducing a color pattern, e.g. a character or an image, is placed between a volume hologram photosensitive material and the reflection type hologram original plate, thereby duplicatively recording a reflection type volume hologram having a color pattern, e.g. a character or an image, together with the shadow thereof, recorded therein simultaneously.
The method proposed in the above-described Japanese Patent Application No. Hei 10-56470, in which individual information or variable information displayed on a liquid crystal display is recorded in a superimposed manner, needs to place the liquid crystal display by the side of or over the hologram original plate. This causes the system to be unfavorably complicated. Further, individual information or variable information is recorded on the basis of the pixels of the liquid crystal display, and the additional information is expressed in the form of a set of pixels. Therefore, the proposed method is inferior in the graphical design function of the hologram. Furthermore, the additional information recorded in a superimposed manner is a simple plane pattern and hence cannot cast a shadow or the like. Thus, the conventional method is inferior in expressional capability as well.
Japanese Patent Application No. 2000-4617 allows a color pattern, e.g. a character, together with the shadow thereof, to be recorded simultaneously and hence provides abundant expressional capability. However, the additional information is limited to the pattern recorded on the character hologram plate. Therefore, it is difficult to record variable information, e.g. a serial number, for each individual hologram made by holographic duplication. Further, the color pattern, e.g. character, and the shadow thereof are in a complementary color relation to each other. Accordingly, it has heretofore been impossible to record the shadow of the same color as that of the color pattern.